U.S. patent application number 15/799410 was filed with the patent office on 2018-05-03 for unit for the regulation or control of a fluid pressure.
The applicant listed for this patent is MANN+HUMMEL GmbH. Invention is credited to Lukas Bock, Heinz Fuchs, Herbert Jainek, Thomas Jessberger, Juergen Kosicki, Volker Kuemmerling, Thomas Schleiden, Thomas Tschech.
Application Number | 20180119835 15/799410 |
Document ID | / |
Family ID | 61912299 |
Filed Date | 2018-05-03 |
United States Patent
Application |
20180119835 |
Kind Code |
A1 |
Bock; Lukas ; et
al. |
May 3, 2018 |
Unit for the Regulation or Control of a Fluid Pressure
Abstract
Disclosed is a method and a unit (10) for the regulation or
control of a fluid pressure, having at least one housing section
(13, 14) and a switching film (22) connected to the at least one
housing section (13, 14) for switching at pressure differentials of
1 to 250 mbar, preferably from 1 to 100 mbar, relative to an
ambient pressure acting on the switching film (22), and for the
regulation, release or blocking of a flow of the fluid between an
inlet (28) and a discharge (30) for the fluid. The switching film
(22) is made out of a polymer material having fluorine and carbon.
In this arrangement, a hole cross-section (40) of the at least one
housing section (13, 14) is closed off by the switching film
(22).
Inventors: |
Bock; Lukas;
(Bietigheim-Bissingen, DE) ; Kuemmerling; Volker;
(Bietigheim-Bissingen, DE) ; Jessberger; Thomas;
(Asperg, DE) ; Fuchs; Heinz; (Benningen, DE)
; Schleiden; Thomas; (Oberstenfeld, DE) ; Kosicki;
Juergen; (Erligheim, DE) ; Tschech; Thomas;
(Marbach, DE) ; Jainek; Herbert; (Heilbronn,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MANN+HUMMEL GmbH |
Ludwigsburg |
|
DE |
|
|
Family ID: |
61912299 |
Appl. No.: |
15/799410 |
Filed: |
October 31, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01M 2013/0016 20130101;
B29C 65/02 20130101; F01M 2013/0083 20130101; F16K 17/26 20130101;
B29C 66/7212 20130101; B29C 66/71 20130101; B29C 66/1312 20130101;
B29C 66/542 20130101; G05D 16/0658 20130101; B29C 66/322 20130101;
B29C 66/5412 20130101; F16K 17/048 20130101; F01M 13/0011 20130101;
F01M 2013/0044 20130101; B29C 66/71 20130101; B29K 2077/00
20130101; B29C 66/7212 20130101; B29K 2307/04 20130101; B29C 66/71
20130101; B29K 2027/18 20130101; B29C 66/71 20130101; B29K 2027/12
20130101 |
International
Class: |
F16K 17/26 20060101
F16K017/26; F01M 13/00 20060101 F01M013/00; F16K 17/04 20060101
F16K017/04 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 2, 2016 |
DE |
10 2016 013 009.1 |
Claims
1. A pressure regulation unit for the regulation or control of a
fluid pressure, comprising: a pressure regulator housing having at
least one housing section; a fluid inlet port; a fluid discharge
port; a switching film connected to the at least one housing
section and adapted to switch at pressure differentials of 1 to 250
mbar relative to an ambient pressure acting on the switching film;
wherein the switching film is adapted for regulation, release or
blocking of a flow of the fluid between the inlet port and the
fluid discharge port; wherein the switching film is made out of a
polymer material having fluorine and carbon, wherein a first
housing section of the at least one housing section has a first
chamber, the first housing section having a hole through which the
first chamber opens to an exterior of the first housing section,
the hole having a hole cross-section; wherein the hole
cross-section of the at least one housing section is closed off by
the switching film.
2. The pressure regulation unit according to claim 1, comprising at
least one circumferential mating surface situated radially to the
outside of the hole cross-section and radially surrounding the hole
cross-section; wherein the switching film is fixedly and
fluid-tightly connected to the at least one housing section and
covering the hole cross-section.
3. The pressure regulation unit according to claim 1, wherein the
switching film includes a joining region situated radially to the
outside of the switching film, and further comprising: a foam
material integrally and interlockingly connecting the joining
region to the at least one housing section.
4. The pressure regulation unit according to claim 3, wherein the
at least one circumferential mating surface has at least one
circumferential groove formed therein; wherein the foam material is
arranged in the at least one circumferential groove; wherein the at
least one housing section is two housing sections; wherein each of
the two housing section has a circumferential mating surface, the
circumferential mating surfaces adapted to align for mating, the
circumferential mating surface having the at least one
circumferential groove formed therein; wherein the at least one
circumferential groove of each of the two housing sections are
arranged axially opposite each other and/or radially offset when
the pressure regulator housing is closed.
5. The pressure regulation unit according to claim 3, wherein the
joining region is surrounded by the foam material at least
partially, on opposing sides of the switching film.
6. The pressure regulation unit according to claim 3, wherein the
foam material has an activated surface in a region of the adjacent
joining region of the switching film; wherein the activated surface
is directed towards the first chamber of the first housing
section.
7. The pressure regulation unit according to claim 4, wherein the
at least one circumferential mating surface of the at least one
housing section is formed conically, curved or undulated such that
the at least one circumferential mating surface is self-adjust for
mating.
8. The pressure regulation unit according to claim 4, wherein the
least one circumferential groove is radially delimited on the
inside by an edge for supporting the switching film when there are
axial movements of the switching film transverse to the hole
cross-section; wherein the edge is provided radially inside the at
least one circumferential mating surface of the at least one
housing section; wherein two axial opposing and/or radially offset
grooves are provided with the edge.
9. The pressure regulation unit according to claim 4, wherein the
two housing sections are the first housing section and a second
housing section; wherein the second housing section has a second
chamber; wherein the first chamber is separated from the second
chamber in a fluid-tight manner by the switching film.
10. The pressure regulation unit according to claim 4, wherein the
polymer material of the switching film fluorine and carbon is: a
polytetrafluoroethylene, or a polytetrafluoroethylene with
admixtures, or a thermoplastically processable
polytetrafluoroethylene.
11. A method of forming a fluid-tight connection of a switching
film onto at least one housing section of a pressure regulator
housing of a pressure regulation unit according to claim 4,
comprising the steps of: providing a switching film formed from a
polymer material having fluorine and carbon, the switching film
having a joining region; providing foam material adapted to fixedly
connect the switching film onto at least one housing section;
providing a first housing section having a first chamber, the first
chamber surrounded by at least one circumferential groove formed
into a mating surface of the first housing section; providing a
second housing section having a second chamber, the second chamber
surrounded by at least one circumferential groove formed into a
mating surface of the second housing section; incorporating the
foam material into the at least one circumferential groove of the
first housing section; placing the switching film onto at least one
of the housing sections with the joining region arranged over and
contacting the foam material; thermally activating the foam
material to increase the volume of the foam material; forming a
fluid-tight connection between the switching film and at least one
of the housing sections.
12. The method according to claim 11, wherein the joining region of
the switching film is surrounded by the foam material at least
partially, on both axial sides of the switching film.
13. The method according to claim 12, wherein wherein the thermally
activating step is practiced by: activating the foam material in an
open foaming arrangement, or activating the foam material with the
foam material chambered within a separate mold, or activating the
foam material with the foam material chambered through the
housing.
14. The method according to claim 12, wherein prior to the step of
placing the switching film, the method further comprises:
pretreating the joining region by at least one of the methods:
etching, plasma treatment, mechanical grinding, embossing or
perforation.
Description
TECHNICAL FIELD
[0001] The invention relates to a unit for the regulation or
control of a fluid pressure, in particular for the pressure
regulation of an internal combustion engine and/or of the crankcase
of the internal combustion engine of a motor vehicle and a method
for fluid-tight connection of a switching film to at least one
housing section of the unit.
BACKGROUND
[0002] Pressure regulating valves are used, for example, in the
breather line between crankcase and intake manifold of an internal
combustion engine. This involves not allowing the pressure or
vacuum in the receptacles to be vented to increase beyond a
predetermined value.
[0003] In internal combustion engines, blow-by gases occur that are
produced by combustion gases in the cylinder getting past the
cylinder piston into the crankcase. These blow-by gases allow the
pressure in the crankcase to rise, whereby leaks and spillages of
oil can be the result. In order to prevent a pressure increase and
to discharge these blow-by gases in an environmentally friendly
manner, these are conducted from the crankcase back into the air
feeder line of the internal combustion engine. Furthermore, the
specified negative pressure value should not be significantly
undershot, because otherwise undesired air can be erroneously
sucked into the crankcase.
[0004] In the pressure regulating valves that are currently being
used, an element familiar to a person skilled in the art under the
term "switching membrane" made from elastomer, commonly
fluorosilicone rubber is generally employed. These switching
membranes are very flexible because of the specific properties of
elastomers. Depending on the applied pressure ratios, this
switching membrane opens or closes an opening in the pressure
regulating valve. The pressure ratio generally results from the
pressure differential between the applied pressure in a first
chamber and the pressure prevailing in a second chamber of the
pressure regulating valve. The pressure in the first chamber may
for example be the same as the atmospheric pressure. The switching
membrane must react to low switching pressures on the order of 1 to
250 mbar.
[0005] Blow-by gases in an internal combustion engine are made up
of unburned fuel components, motor oil components and other
pollutants resulting from the combustion. These gases attack many
elastomer types, whereby damages to the material properties can
occur. The components made from these materials become brittle,
porous and cracked. If the switching films are damaged, the
environmentally damaging blow-by gases pass directly into the
environment, because the system is no longer sealed. The switching
membrane made from elastomer is generally executed as roll film, in
order to realize a specific stroke of the switching membrane. The
material in the roll region is also mechanically damaged through
the unrolling motion by simultaneous contact with blow-by gases and
can thus be damaged.
[0006] The DE 26 29 621 A1 discloses a diaphragm valve having a
switching membrane that is designed as a switching film clamped at
its edge between the housing and the housing cover which is to be
brought into a sealing contact by a pressure member against a
seating surface provided in the housing, wherein the switching
membrane is made of a thinner layer of low elasticity, for example
from PTFE, facing towards the housing interior that is resistant to
aggressive through-flow media, and an additional, thicker layer
made of elastomeric material. Diaphragm valves of this type are
primarily used where a high chemical resistance of the materials
coming into contact with the through-flow medium is required.
Because elastomeric materials do not meet this requirement but the
chemically resistant materials such as PTFE do not possess the
elasticity necessary for a proper function, films comprising two
layers are used. The contact pressure that is applied by the
pressure member via the thick, rubber-like layer is transmitted as
evenly as possible onto the sealing surface of the switching film
that works together with the seating surface in the housing. In
this arrangement, relatively large switching pressures of several
bar are exerted on the switching membrane for closing the
two-layered switching membrane via a pressure spindle that is
connected to a hand wheel in order to ensure the necessary sealing
function by the stiff PTFE layer.
SUMMARY OF THE INVENTION
[0007] It is one object of the invention to create a unit for
switching at low pressure differentials that achieves high
operational life during operating modes on an internal combustion
engine having aggressive media, in particular from so-called
blow-by gases
[0008] It is an additional object of the invention to create a
method for fluid-tight connection of a switchable closing element
to the unit, that achieves a high operational life during operation
in an internal combustion engine having aggressive media, in
particular from so-called blow-by gases.
[0009] The aforementioned object is achieved according to one
aspect of the invention by a unit for regulation or control of a
fluid pressure and of a switching film connected to at least one
housing section, wherein the switching film is formed from a
polymer film from a polymer material having fluorine and carbon and
wherein a hole cross-section of the at least one housing section is
closed off by the switching film.
[0010] According to another aspect of the invention, the additional
object is achieved by a method for fluid-tight connection of a
switching film to at least one housing section or a unit, wherein
the switching film is integrally and/or interlockingly connected to
the at least one housing section using foam material.
[0011] Favorable embodiments and advantages of the invention are
disclosed in the further claims, the description and the
drawings.
[0012] A unit is proposed for the regulation or control of a fluid
pressure, having at least one housing section and a switching film
connected to the at least one housing section for switching at
pressure differentials of 1 to 250 mbar, preferably from 1 to 100
mbar, relative to an ambient pressure acting on the switching film,
and for the regulation, release or blocking of a flow of the fluid
between an inlet and a discharge for the fluid, wherein the
switching film is made out of a polymer material having fluorine
and carbon, and wherein a hole cross-section of the at least one
housing section is closed off by the switching film.
[0013] The unit does not only serve to release or shut off a
through-flow, but regulates between the two switching states
"release" or "shut off" by a continuous alteration of the
through-flow cross-section as a function of the pressure
differential on the through-flow of fluid between the inlet and the
discharge. In this manner, the through-flow can be restricted.
[0014] The polymer film having fluorine and carbon is chemically
resistant and can switch many switching cycles of the film valve.
The long-term stability of the unit is improved. In particular, the
polymer film having fluorine and carbon can be PTFE
(polytetrafluorethylene). Alternatively, the polymer having
fluorine and carbon can be made of a PTFE as the base material,
which has admixtures, in particular an admixture of glass fiber,
glass spheres, graphite and/or carbon fibers, in particular having
a proportion of the admixed substances of up to 60%; similarly, the
polymer having fluorine and carbon can be a thermoplastically
processable PTFE, which is processable in a spraying process, in
particular. Preferably, the switching film is at most 0.5 mm thick,
preferably at most 0.3 mm, particularly preferably at most 0.2 mm
thick. The switching film can have a diameter between 40 mm and 100
mm, preferably between 50 mm and 80 mm. It is possible that with
correspondingly large diameters somewhat higher thickness of the
switching film in the region of over 0.5 mm, for example at most
0.5 mm to 1 mm, can be realized.
[0015] A conventional switching membrane made from elastomer of a
conventional unit for pressure regulation of an internal combustion
engine and/or the pressure regulation of the crankcase of an
internal combustion engine is replaced here by a switching film
made from the polymer having fluorine and carbon. A polymer
material having fluorine and carbon such as PTFE can, for example,
be manufactured in a sintering process and then mechanically
processed. Such a switching film in its normal form is very stiff
and actually not appropriate for flexible components. PTFE has an
outstanding chemical resistance and can be used in a very broad
range of temperatures, wherein the modulus of elasticity is very
sharply increased at low temperatures compared to elastomeric
materials. For this reason, PTFE is not appropriate for an
application as switching film in the temperature range required for
automotive applications in an internal combustion engine of
typically -40.degree. C. to +150.degree. C. This disadvantage is
avoided in the unit according to the invention by virtue of an
advantageous geometry and optionally by an extremely thin wall
thickness of the switching film made from the polymer having
fluorine and carbon. By reducing the wall thickness of the PTFE
material in the switching film in an intentionally movable range of
a few tenths of a millimeter, wherein the intentionally fixed
thickness range as well as the clamping region of the material can
also be executed thicker, and a specially developed geometry of the
switching film without roll region, as it is conventionally used in
prior art, the stiff material is formed into a shape in which it
has the necessary flexibility, but nevertheless fulfills the
mechanical requirements with respect to crack formation, strain and
fatigue strength under reversed bending stresses. By virtue of the
special geometry, roll motion no longer takes place, rather a
bending motion can be realized having a radius change that can be
accomplished with low strain or even practically no strain of the
material and with which a lifting motion of the switching film for
the unit according to the invention can be implemented.
[0016] The switching film can have a plate-like flat body, in
particular formed as plate-shaped flat body, having a bending
region surrounding a central sealing region, wherein the bending
region moves the sealing region in an axial direction with respect
to a valve seat, meaning in the direction normal to the flat body,
onto the valve seat or away from the valve seat during switching of
the switching film by a low-strain--meaning practically strain-free
for practical application, in particular strain-free--bending
motion. Because the switching film in this embodiment can flex not
only in a small surface region, but broadly because of the
plate-like shape, individual regions of the switching film are
hardly or practically not at all strained. The bending motion is
thus executed across a large region of the switching film--and,
consequently, with little elastic deformation--in the form of a
curvature change with low strain, for example less than 10%.
[0017] The sealing region of the switching film can interrupt the
through-flow of the fluid between the inlet and the discharge. The
switching film can, for example, be located with its sealing region
against a seal seat in order to interrupt the through-flow.
[0018] For this purpose, the switching film can be movable between
its respective maximum positions in the opened and closed state by
application of atmospheric pressure as control pressure on one side
of the switching film. Advantageously, the switching film can be
self-regulating and the switching film can be closed indirectly via
a pressure differential between atmospheric pressure in the one
chamber of the unit and an operating pressure of the other chamber
of the unit. The operating pressure can, for example, be a pressure
in a crankcase of an internal combustion engine.
[0019] Advantageously, the switching film can alternatively be
movable between its respective maximum positions in the opened and
closed state, if on one side of the switching film a control
pressure is applied that does not equal an atmospheric pressure
and/or a mechanical actuating means is provided to switch the
switching film.
[0020] Via a spring element, which is supported against the at
least one housing section, a force is applied to the switching film
in order to be able to adjust the control response of the unit. For
this purpose, the discharge can have a valve seat arranged at an
end in the housing section, which is sealable by the sealing region
of the switching film, whereby a discharge of fluid from the inlet
to the discharge can be regulated. The spring element in this
arrangement exerts the appropriate counterforce on the switching
film to achieve a control response of the unit in the desired
pressure region. The side of the switching film facing away from
the fluid to be regulated is generally supplied here with
atmospheric pressure.
[0021] According to the invention, a hole cross-section of the at
least one housing section of the unit is closed off fluid-tight by
an operating region of the switching film. In this manner the
through-flow of the unit can be regulated, released, shut off or
limited. An edge region surrounding the operating region of the
switching film allows a fluid-tight connection of the switching
film made from a polymer having fluorine and carbon against the
housing of the unit, which can be advantageously made from plastic,
for example, glass-fiber reinforced polyamide (PA), and represents
an additional great advantage over the prior art, in which the
impermeable or closed membranes have no claim to tightness, rather,
they are only interlockingly connected to the housing. By virtue of
the fluid-tight connection, a region of the unit is advantageously
guaranteed to be sealed as fluid-tight, for example as a pressure
regulation valve, because the switching film can in each case seal
a housing section fluid-tight by being fixedly connected to the
housing section, as well as sealing of the interior spaces of two
housing sections against each other, if the first housing section
is sealed with a second housing section, such as with a housing
cover.
[0022] According to one advantageous embodiment, at least one
circumferential mating surface can be provided situated radially to
the outside on the at least one housing section at which the
switching film is connected, in particular fixedly connected, in
particular is fixedly and fluid-tightly connected to the at least
one housing section. By the fixed connection of the switching film
to the outer radially circumferential mating surface, the central
inner region of the switching film can move freely as a whole in
the axial direction and as a sealing region of the switching film
can thus exercise the actual switching function of the unit, for
example as pressure regulation valve. Through the fluid-tight
connection of the switching film against at least one housing
section, it can also be effectively prevented that possible
outgassing of the material into the environment.
[0023] According to one advantageous embodiment, a radially
outwards situated joining region of the switching film can be
connected to the at least one housing section by foam material, in
particular integrally and/or interlockingly. An integral and/or
interlocking connection of the switching film with the mating
surface of the housing section can ensure the fluid-tight seal of
the hole cross-section of the housing section as well as the fixed
and durable connection of the switching film for a safe function
during the operating mode of the unit.
[0024] The switching film that can advantageously first be
subjected to a surface treatment can be connected to at least one
connecting element, for example a housing section. The foam
material can hereby be chambered by a tool such as an additional
cover or a separate hold-down device that is only necessary for the
process step, or chambered by a housing section, or applied openly
foamed. Foam material is generally understood to be a material
composition that can be brought into the aggregate state as firm or
fluid. After the application, the foam material is activated by
intrinsic action or by external influence and increases its volume.
For example, the foam material can be thermally activated. After
finishing the activation process, the foam material can be elastic,
inelastic, flexible or hard.
[0025] According to one advantageous embodiment, at least one
circumferential groove can be provided in the mounting surface of
at least one housing section for housing of the foam material. The
foam material can in this manner be effectively incorporated into
the groove and thus distributed on the mounting surface of the
housing section in a targeted manner during compression by the
switching film against the housing section, whereby a fluid-tight
and durable connection can be achieved.
[0026] In particular, a groove can be advantageously provided in
the mounting surfaces of each of the two housing sections for
housing of the foam material, wherein the grooves are arranged in
the closed housing axially opposing each other and/or radially
offset. The foam material, which stretches after activation and can
greatly increase it volume, can thus be incorporated into the
grooves on the two sides of the joint so that the two housing
sections can nonetheless clamp the switching film and abut each
other in a fluid-tight manner. A durable and reliable fluid-tight
connection between housing and switching film or a reliable sealing
of the hole cross-section of the unit can thus be achieved.
[0027] According to one advantageous embodiment, the joining region
of the switching film can be enclosed at least partly, in
particular on both sides, by the foam material. In this manner, the
switching film is embedded in the foam material and firmly
connected to this. In particular, the switching film can be
enclosed on both sides of its joining region by the foam material,
which ensures a reliable and durable connection between switching
film and housing section. A reliable, fluid-tight sealing of the
hole cross-section of the unit is thus also achieved.
[0028] According to one advantageous embodiment, the switching film
can, at least in the region of the joining region, have at least
one activated surface, in particular at least one activated surface
directed toward a first chamber of the first housing section. For
preparation of the connection using a foam material, it can be
advantageous to accordingly prepare the surface of the switching
film in that region where it comes into connection with the foam
material in order to change the surface tension. Such an activation
can thus expediently include one or more methods such as etching,
plasma treatment, mechanical roughening, stamping, perforating or
similar, appropriate methods. The contact between the foam material
and the switching film can thereby be improved. Moreover, it is
beneficial to subject a surface of the switching film that is
exposed to the fluid, such as is the case in the first chamber of
the first housing section, for example, to a treatment by
activation.
[0029] According to one advantageous embodiment, the mating surface
of the at least one housing section can be formed to be
self-adjusting in a longitudinal direction. In particular, the
mating surface can be formed conically or curved upwards or
downwards or corrugated. By virtue of the self-adjusting mating
surface, a particularly good connection of a different housing
section as well as of the switching film can be ensured with
automatic centering of the first housing section or of the
switching film before and during the process of the connection.
[0030] According to one advantageous embodiment, at least one
radially circumferential groove can be provided radially inside the
mating surface of the at least one housing section and radially
delimited on the inside by an edge for supporting the switching
film when there are axial movements transverse to the hole
cross-section, wherein in particular two axial opposing and/or
radially offset grooves can be provided with an edge, in particular
a raised lip. A raised lip on the edge advantageously supports
dynamic movements of the switching film with its working region
during the execution of the function in the pressure valve and
simultaneously achieves a protection against damage by the motion
of the switching film. As a result, the switching film always rests
against at least one edge during its switching motion, preferably
however, at two edges simultaneously. In order to prevent a damage
to the switching film during the joining process such as, for
example, by an unacceptable compression of the switching film by
the edges, the edges can be arranged radially offset. A realization
of a connection is thus easier, in that the switching film is
located on two edges simultaneously. A movement on the boundary
surface to an edge can then be prevented. The edge can be optimized
for the film motion so that the switching film in operation is
protected against damage by the edge. It is also possible to apply
a prestress of the switching film via these edges.
[0031] According to one advantageous embodiment, a housing can be
provided with the first housing section and a second housing
section, and the first chamber can be separated fluid-tight from a
second chamber by the switching film. The second chamber of the
unit can thus be supplied with an atmospheric pressure. For an
effective control response of the unit, the switching film should
be able to move as freely as possible, for which reason the second
chamber, which is separated by the functional region of the
switching film from the first chamber, in which the fluid to be
controlled is located, is expediently in connection with the
environmental region, meaning with the atmospheric pressure.
[0032] According to one advantageous embodiment, the polymer
material having fluorine and carbon is polytetrafluoroethylene or
polytetrafluoroethylene with admixtures or thermoplastically
processable polytetrafluoroethylene.
[0033] According to a different aspect of the invention, a method
for the fluid-tight connection of a switching film to at least one
housing section of a housing of a unit is proposed, wherein the
switching film is formed from a polymer material having fluorine
and carbon, and wherein a joining region of the switching film
situated radially to the outside that is integrally and/or
interlockingly connected in the region of at least the mating
surface to the at least one housing section by foam material. The
method thus comprises an introduction of the foam material in firm
or fluid form into at least one circumferential groove of the at
least one housing section, followed by a seating of the switching
film on the at least one housing section having the joining region
over the foam material. Finally, the foam material is foamed by
intrinsic action or by outside influence, in particular through
thermal activation. After compressing the switching film with the
housing section and curing of the foam material, a durable and
fluid-tight connection of the switching film at the housing section
and thus a fluid-tight sealing of the hole cross-section of the
housing section can thus be achieved.
[0034] The switching film, which can first be subjected to a
surface treatment, can be connected to at least one connection
element, for example a housing section. Foam material is generally
understood to be a material composition that can be brought into
the aggregate state as firm or fluid. After application, the foam
material is activated by intrinsic action or by outside influence
and increases its volume. For example, the foam material can be
thermally activated. After finishing the activation process, the
foam material can be elastic, inelastic, flexible or hard.
[0035] According to one advantageous embodiment, the joining region
of the switching film can be enclosed at least partly, in
particular on both sides, by the foam material. In this manner, the
switching film is embedded in the foam material and firmly
connected to this. In particular, the switching film can be
enclosed with the foam material on both sides of its joining
region, which ensures a reliable and durable connection between the
switching film and the housing section. A reliable, fluid-tight
sealing of the hole cross-section of the unit is thus also
achieved.
[0036] According to one advantageous embodiment, the foam material
can be freely foaming or chambered in a separate tool or be foamed
chambered by the housing. The foam material can hereby be chambered
by a tool such as an additional cover, a separate hold-down device
that is only necessary for the process step, or chambered by a
housing section, or processed openly foamed.
[0037] According to one advantageous embodiment, the joining region
of the switching film is pretreated by at least one of the methods,
etching, plasma treatment, mechanical grinding, embossing or
perforation. For pretreatment of the connection using a foam
material, it is advantageous to accordingly pretreat and activate
the surface of the switching film in the region where it comes into
connection with the foam material, which can be achieved with one
of the procedures mentioned. In this way the surface tension can be
changed, whereby the contact between foam material and switching
film can be essentially improved.
[0038] After the placement of the switching film on the at least
one first housing section having the joining region over the mating
surface, a second housing section is placed on the switching film
and the housing is thus formed. The second housing section can thus
be expediently connected to the switching film and/or the first
housing section. Alternatively, it is also conceivable to radially
weld the two housing sections, which can be formed from, for
example, glass-fiber reinforced polyamide (PA), outside the
switching film.
[0039] Expediently, the joining region of the switching film can be
compressed when the housing is sealed in the region of the mating
surface. By the compression, for example, a greater final strength
of the connection can be achieved. In this way, the fluid-tight
connection can also be favorably improved.
[0040] Advantageously, the switching film can be axially supported
by at least one groove running radially inside the mating surface
in the at least one housing section, which is radially delimited
inside by a projection for supporting the switching film during
axial movements transverse to its cross-sectional area. In this
way, dynamic movements of the switching film during the execution
of the function in the pressure regulating valve can be
advantageously supported and, at the same time, a protection
against damage by the movement of the switching film can be
achieved. The switching film is thereby always located on at least
one edge, preferably however at two edges simultaneously during its
switching motion. In order to prevent a damage to the switching
film during the joining process such as, for example, by an
unacceptable compression of the switching film by the edges, the
edges can be arranged radially offset. A realization of a
connection is thus easier, in that the switching film is located on
two edges simultaneously. A movement on the boundary surface to an
edge can then be prevented. The edge can be optimized for the film
movement so that the switching film is protected against damages by
the edge during operating mode.
[0041] Advantageously, the switching film can also be axially
supported by two grooves arranged in the housing with an edge,
which are arranged opposite each other or radially displaced
relative to each other. In this further embodiment, the edges of
the housing section can be mutually shifted so that the switching
film is not crimped in this region during the joining process. It
is also possible to adjust the pretension of the switching film via
these edges.
[0042] According to a further aspect of the invention, the unit
according to the invention is used for pressure regulation of an
internal combustion engine and/or for pressure regulation of a
crankcase of an internal combustion engine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Further advantages arise from the following drawing
description. The drawings show exemplary embodiments of the
invention. The drawings, the description and the claims contain
numerous features in combination. The person skilled in the art
will expediently consider the features individually and combine
them into meaningful further combinations. In the drawings, by way
of example:
[0044] FIG. 1 a unit having a switching film made from a polymer
with fluorine and carbon according to an exemplary embodiment of
the invention in a sectional view;
[0045] FIG. 2 a unit having a switching film according to an
additional exemplary embodiment of the invention in a sectional
view;
[0046] FIG. 3 a simplified section of a joining region of a unit in
a sectional view before activation of foam material using a tool
according to one exemplary embodiment of the invention;
[0047] FIG. 4 the section of the joining region from FIG. 3 with
activated foam material after removal of the tool;
[0048] FIG. 5 a simplified section of a joining region of a unit in
a sectional view with foam material introduced in two grooves
according to a further exemplary embodiment of the invention;
[0049] FIG. 6 the simplified section of the joining region in FIG.
5 with activated foam material;
[0050] FIG. 7 a simplified section of a joining region of a unit in
a sectional view with foam introduced into a groove according to an
additional exemplary embodiment of the invention;
[0051] FIG. 8 the simplified section of the joining region in FIG.
7 with activated foam material;
[0052] FIG. 9 a simplified section of a joining region of a unit in
a sectional view with two grooves and introduced foam material
according to a further exemplary embodiment of the invention;
and
[0053] FIG. 10 the simplified section of the joining region from
FIG. 9 with activated foam material.
DETAILED DESCRIPTION
[0054] The same or similar components in the figures are referenced
with same reference characters. The figures merely show examples
and are not intended to be restrictive.
[0055] FIG. 1 shows a sectional view of a unit 10 for the
regulation or control of a fluid pressure using a switching film 22
made from a polymer having fluorine and carbon according to an
exemplary embodiment of the invention. The polymer material having
fluorine and carbon is thus polytetrafluoroethylene or
polytetrafluoroethylene with admixtures or thermoplastically
processable polytetrafluoroethylene particularly in a spraying
process. The unit 10 serves for regulation or control of a fluid
pressure, in particular for application for pressure regulation of
an internal combustion engine and/or for the pressure regulation of
a crankcase of an internal combustion engine. The unit 10 has a
housing 12 with a first housing section 13 and a second housing
section 14, the housing cover, wherein the first housing section 13
has an inlet 28 and a discharge 30 for the fluid. The switching
film 22 is formed from a polymer film having fluorine and carbon,
for example PTFE, and clamped with a joining region 42 between
first housing section 13 and the second housing section 14.
[0056] The hole cross-section 40 of the two housing sections 13, 14
is sealed by the switching film 22 with its functional region. Two
circumferential mating surfaces 50, 52 are provided situated
radially to the outside on the two housing sections 13, 14, at
which the switching film 22 is connected fluid-tight to the two
housing sections 13, 14. In the exemplary embodiment shown, a
joining region 42 of the switching film 22 is thus, in particular,
integrally and/or interlockingly connected to the two housing
sections 13, 14 by foam material 44. The foam material 44 is thinly
introduced into the region of the joining region 42 of the
switching film 22 between the mating surfaces 50, 52 of the two
housing sections 13, 14 and therefore cannot be seen in FIG. 1 as
also in FIG. 2. Optional favorably arranged grooves for housing of
the activated foam material 44 are not shown for reasons of
clarity. In each of the exemplary embodiments in FIGS. 1 and 2, the
connection of the joining region 42 of the switching film 22 via
foam material 44 in a groove 46 of the first housing section 13 is
schematically represented. Possible additional embodiments of the
connection of the joining region 42 are shown in detail in FIGS. 3
to 10 in simplified sections.
[0057] The switching film 22 separates a first chamber 36 of the
unit 10 from a second chamber 38 in a fluid-tight manner. There is
a pressure differential between the first chamber 36 and the second
chamber 38, wherein the second chamber 38 is connected (not
depicted) to the surrounding space, meaning to the atmosphere. The
switching film 22 can be moved with pressure differences of 1 to
250 mbar, preferably from 1 to 100 mbar, and serves to release or
shut off a through-flow of the fluid between the inlet 28 and the
discharge 30. The inlet 28 of the unit 10 is fluidically connected
during use to, for example, the crankcase of an internal combustion
engine, while the discharge 30 is fluidically connected to the
breather line. The switching film 22 has a plate-like flat body 16
having a corrugated bending region 18 surrounding a central sealing
region 24. The bending region 18 moves during switching of the
switching film 22 by a low-strain, in particular strain-free
bending motion of the sealing region 24 with respect to a valve
seat 32 in an axial direction L toward the valve seat 32 or away
from the valve seat 32. For this, the switching film 22 has at
least in the bending region 18 a thickness of at most 0.5 mm,
preferably of at most 0.3 mm, most preferably of at most 0.2 mm.
The diameter of the switching film 22 can thus be between 40 mm and
100 mm, preferably between 50 mm and 80 mm.
[0058] The bending region 18 extends in a wave-like manner in
radial direction around sealing region 24, wherein a recess on a
flat side corresponds to an elevation on the other flat side of the
switching film 22. The sealing region 24 seals the valve seat 32 if
it is located on the valve seat 32. A spring element 26 is provided
that is supported at the first housing section 13 which exerts a
force on the sealing region 241 of the switching film 22. The
spring element 26 is supported here by an annularly formed plate 34
at the sealing region 24. The sealing region 24 is formed as a
bowl-shaped projection 20 of the switching film 22, wherein the
plate 34 in the form of a support ring annularly encloses this
projection. The spring element 26 can alternatively engage the
switching film 22 without plate 34 and thus be sprayed on its end
face that is turned towards the projection 20 for protection of the
switching film 22, so that the encapsulation can replace the plate
34.
[0059] A groove 54, 56 running radially is provided inside the
mating surface 50, 52 of each of the two housing sections 13, 14,
which is delimited radially inside by an edge 58, 60 for supporting
the switching film 22 during axial movements transverse to the hole
cross-section 40. The two grooves 54, 56 are located axially
opposite one another. Because the switching film 22 is located on
the rounded edges 58, 60 and is clamped between them, the switching
film 22 is protected against excessive wear and damages from sharp
edges resulting from axial movements of its working region because
of the regulating function of the unit 10.
[0060] Advantageously, the switching film 22 in this arrangement,
at least in the region of the joining region 42, has an activated
surface with altered surface tension in order to achieve a good
connection to the foam material 44, wherein the joining region 42
is prepared, for example, by one of the methods, etching, plasma
treatment, mechanical roughening, embossing or perforation. After
the seating of the switching film 22 on the at least first housing
section 13 having the joining region 42 over the foam material 44,
a second housing section 14 is seated on the switching film 22 and
thus forms the housing 12. The joining region 42 of the switching
film 22 is compressed during the sealing of the housing 12 in the
region of the mating surfaces 50, 52. A curing of the foam material
44 can be enhanced by a heat treatment and/or a UV radiation and/or
a microwave treatment.
[0061] FIG. 2 shows in a cross-sectional view a unit 10 having a
switching film 22 according to an additional exemplary embodiment
of the invention. The basic design of the unit 10 essentially
corresponds to the exemplary embodiment in FIG. 1. The mating
surfaces 50, 52 of the two housing sections 13, 14, however, are
formed conically in the longitudinal direction L. In this manner,
the switching film 22 can advantageously be centered during the
joining of the switching film 22 at the first housing section 13
and during assembly of the housing 12 by placement of the second
housing section 14. The grooves 54, 56 with their edges 58, 60--in
contrast to the embodiment in FIG. 1 where they are arranged
axially opposed--are arranged in this case radially displaced,
which can also be beneficial for the support of the switching film
22 during the axial movement of the switching film 22.
[0062] FIG. 3 shows a simplified section of a joining region 42 of
a unit 10 in a sectional view before activation of foam material 44
introduced into a groove 46 using a tool 70 according to one
exemplary embodiment of the invention. The first housing section 13
has a groove 46 running radially, which lies opposite a groove 72
running radially in the tool 70 with a small depth. The foam
material 44 is introduced into the groove 46 of the first housing
section 13. Afterwards, the switching film 22 is seated on the
first housing section 13 and covered by the tool 70, which is
designed, in particular as a hold-down device. In this manner, the
foam material 44 can be foamed chambered. The foam material 44 can
be activated, in particular, thermally activated. The foam material
44 thus stretches in the open space formed by the grooves 46, 72 so
that it can at least partially enclose the switching film 22 with
its joining region 42. Joining region 42 and mating surface 50 of
the housing section 13 are thus firmly connected fluid-tight with
each other. After activation of the foam material 44, the tool 70
can be removed.
[0063] FIG. 4 also shows the section from FIG. 3 with the activated
foam material 44 after removal of the tool 70. The foam material 44
is thereby activated using the positioned tool 70, is thereby
foamed and thus fills the groove 46. The foam material 44 swells
out over the groove 46 and thus encloses the joining region 42 of
the switching film 22, at least on its radial outer edge.
[0064] In FIG. 5, a simplified section of a joining region 42 of a
unit 10 is shown in a sectional view with the foam material 44
introduced in two grooves 46, 64 according to a further exemplary
embodiment of the invention. The two axially opposed,
circumferential grooves 46, 64 are thus shown having the same
groove depth. Foam material 44 is introduced into each groove 46,
64. The switching film 22 is located with its joining region 42
between the two housing sections 13, 14 and is additionally fixed
against activation of the foam material by clamping.
[0065] FIG. 6 also shows the simplified section of the joining
region 42 from FIG. 5 with activated foam material 44. The foam
material 44 is foamed and completely fills the grooves 46, 64. The
foam material 44 thus encloses the switching film 22 on both sides
and thus provides for the firm connection between the joining
region 42 and the mating surfaces 50, 52 of the two housing
sections 13, 14. A firm, fluid-tight connection is thus created
between the housing section 12 and the switching film 22.
[0066] In FIG. 7, a simplified section of a joining region 42 of a
unit 10 is shown in a sectional view with the foam 44 introduced
into a groove 46 according to an additional exemplary embodiment of
the invention. In this exemplary embodiment a radially running
groove 46 into which the foam material 44 is introduced is only
arranged in the first housing section 13. The second housing
section 14 thus has a continuously flat mating surface 52, which is
located abutting the switching film 22 when the second housing
section 14 is seated.
[0067] FIG. 8 shows the simplified section of the joining region 42
from FIG. 7 with activated foam material 44. The foam material 44
in this exemplary embodiment completely fills the groove 46 and
tightly seals the switching film 22 to the joining region 42, in
particular, the foam material 44 is integrally and/or
interlockingly connected to the joining region 42.
[0068] FIG. 9 shows a simplified section of a joining region 42 of
a unit 10 in a sectional view with two grooves 46, 64and introduced
foam material 44 according to a further exemplary embodiment of the
invention. The first housing section 13 has a groove 46 running
radially, which is axially arranged with respect to a groove 64
having reduced depth running radially in the second housing section
14. Foam material 44 is introduced into the first groove 46. The
joining region 42 of the switching film 22, which is seated between
the two housing sections 13, 14, projects to a part having its
radial outer edge in the open space formed by the grooves 46,
64.
[0069] In FIG. 10, the simplified section of the joining region 42
from FIG. 9 with activated foam material 44 is also shown. The foam
material 44 is foamed and completely fills the open space of the
grooves 46, 64. The joining region 42 of the switching film 22 is
thus enclosed at a part at the underside and the radial outer edge
by the foamed material 44. The two housing sections 13, 14 are thus
connected fluid-tight to the joining region 42 of the switching
film 22.
* * * * *